Doctors recommend getting your flu shot annually, since the specific influenza strain it targets varies from year to year. But what if the shot could be more effective while protecting against more strains?
Researchers from the University of Missouri School of Medicine are one step closer to making this happen. When the immune system sees a new strain of a familiar virus, it typically focuses on the parts it ‘remembers’ most, even if those regions have changed.
“In our vaccine model, we targeted specific but distinct regions of the protein on the surface of the influenza virus. These regions are called epitopes,” said study author Henry Wan. “The model included different versions of epitopes in hopes of redirecting how the immune system responds. We found that the vaccine approach helped the immune system target more variants of the virus, leading to broader protection.”
Wan says the epitopes help the immune system see the flu virus differently, and it learns to respond with more coordination between the different types of immune cells. Some of the epitopes are also not as likely to change, which could make flu vaccines more reliable or even help create a universal flu vaccine.
“Right now, current influenza vaccines primarily trigger immune responses to the entire protein, especially in the highly variable region, instead of focusing on parts that don’t change much,” Wan said. “So, when changes happen – which is likely – the immune system may not respond effectively or activate its ‘memory’ after re-exposure.”
If targeting epitopes works in humans, this method could be adopted to fight other fast-changing viruses, like COVID-19 or RSV.
“These upper respiratory infections are a major public health concern and contribute to thousands of deaths per year,” Wan said. “Anything we can do to improve the influenza vaccine can help save lives and keep people out of the hospital.”
Xiu-Feng (Henry) Wan, PhD is a professor of Molecular Microbiology and Immunology; Veterinary Pathobiology; and Electrical Engineering and Computer Science at the Mizzou School of Medicine and the Colleges of Veterinary Medicine and Engineering. He directs the NextGen Center for Influenza and Emerging Infectious Diseases, which aims to understand and prevent the spread of infectious diseases. He is also a Curators’ Distinguished Professor and a principal investigator at the NextGen Precision Health Building and at Bond Life Sciences Center.
“Epitope-spanning antigenic variation reprograms immunodominance and broadens immunity in sequential influenza vaccination” was recently published in Nature Communications. In addition to Wan, Mizzou study authors include Minhui Guan, Pradeep Balamalaliyage, Kritika Prasai, Ana Ancala, John Driver, PhD, Weihong Gu, Christina Frymire, De Darling Melany Carvalho Madrid, Cheng Gao, Chengcheng Wang, Wikanda Tunterak, Qiongying Yang, Ashwin Ramesh, Muzaffar Ali and Mingyi Zhou. This research was a collaborative effort involving Rice University (Hanqiao Chen and Jane Tao); Mississippi State University (Alicia Olivier and David Smith); the Walter Reed Army Institute of Research (Jun Hang and Tao Li); the University of Rochester (Andrea Sant); the U.S. Food and Drug Administration (Hang Xie); and Georgia State University (Lei Li).
This study was supported by the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health.
